Name Date Class

ATOMIC STRUCTURE

Practice Problems In your notebook, solve the following problems.

SECTION 4.1 DEFINING THE ATOM 1. According to Figure 5.2, 100,000,000 copper atoms would form a line 1 cm long. How long would a line formed by

1 x 107 copper atoms be? Express your answer in millimeters.

SECTION 4.2 STRUCTURE OF THE NUCLEAR ATOM

1. A sulfur-32 atom contains 16 protons, 16 neutrons, and 16 electrons. What is the mass (in grams) of a sulfur-32

atom?

2. The mass of a neutron is 1.67 x 10-24 g. Approximately what number of neutrons would equal a mass of one gram?

3. Which statement is consistent with the results of Rutherford’s gold foil experiment?

a. All atoms have a positive charge.

b. Atoms are mostly empty space.

c. The nucleus of an atom contains protons and electrons.

d. Mass is spread uniformly throughout an atom.

SECTION 4.3 DISTINGUISHING BETWEEN ATOMS

1. How many protons are found in an atom of each of the following?

a. boron c. neon

b. sulfur d. lithium

2. Complete the table for the following elements.

Element Number of

Protons

Number of

Electrons

Number of

Neutrons

Atomic

Number

Mass

Number

Manganese 25 30

Sodium 11 12

Bromine 35 45

Yttrium 39 89

Arsenic 33 75

Actinium 227

Chapter 4 Atomic Structure 89

Name Date Class

3. How many neutrons are in each atom?

a. c.

b. d.

4. The two most abundant isotopes of carbon are carbon-12 (mass = 12.00 amu) and carbon-13 (mass = 13.00 amu).

Their relative abundances are 98.9% and 1.10%, respectively. Calculate the atomic mass of carbon.

5. Element X has two isotopes: X-100 and X-104. If the atomic mass of X is 101 amu, what is the relative abundance

of each isotope in nature?

90 Core Teaching Resources

23 Na

11 81

Br 35

238 U 92

19 F 9